The present invention relates to catalytic mixtures on the basis of at least partially fluorinated titanium tetrachloride and tin tetrachloride and their use for the production of fluorinated organic compounds.
A large number of catalysts are already known which are suitable for the addition of hydrogen fluoride (HF) and for chlorine-fluorine exchange by means of hydrogen fluoride.
For example, U.S. Pat. No. 5,347,059 (=EP 522,638) discloses a process for the production of 1,1-dichloro-1,3,3,3-tetrafluoropropane from the corresponding hexachloropropane compound. Metals of the groups IIIa, IVa and b, Va and b and group VIb of the periodic table of the elements and their mixtures are cited as catalysts which promote the reaction. Titanium derivatives, tantalum derivatives, molybdenum derivatives, boron derivatives, tin derivatives and antimony derivatives are particularly suitable. Tin derivatives and antimony derivatives are emphasized as being particularly preferred.
U.S. Pat. No. 5,202,509 (=EP 415,814) discloses fluorination catalysts which consist of a mixture of an antimony trihalide and a titanium tetrahalide. These mixtures are suitable, for example, for the fluorination of chlorine derivatives of methane, ethane and ethylene. However, corresponding bromine or iodine derivatives can also be fluorinated.
A. E. Feiring in J. Fluorine Chem. 14 (1979), pages 7 to 18, discloses that TiCl.sub.4 catalyses the addition of HF to tetrachloroethylene. A subsequent chlorine-fluorine exchange leads to the formation of difluorotrichloroethane to a small extent.
Published British Patent Application No. GB 627,773 discloses the addition of hydrogen fluoride to certain C2 and C3 compounds. The catalyst is tin tetrachloride and tin tetrafluoride. In addition to the HF addition, a chlorine-fluorine exchange is also observed.
U.S. Pat. No. 5,395,997 (=WO 95/04021) discloses the production of fluorohydrocarbons from chlorohydrocarbons, which may also be fluorine-substituted, by catalyzed chlorine-fluorine exchange with hydrogen fluoride. Preferably at least one metal halide, selected from the group of halides of tin, titanium, tantalum and antimony is used. The examples operate with antimony pentafluoride, titanium tetrachloride, tin tetrachloride, antimony pentachloride or in the absence of a catalyst.